docs: def load_neurite_features(filepath):
      '''Unpack relevant data into megadict'''
      stuff = defaultdict(lambda: defaultdict(list))
      nrns = nm.load_neurons(filepath)
      # unpack data into arrays
      for nrn in nrns:
          for t in NEURITES_:
              for feat in FEATURES:
                  stuff[feat][str(t).split('.')[1]].extend(
                      nm.get(feat, nrn, neurite_type=t)
                  )
      return stuff